After a hot 5-1 start, the Arizona State Sun Devils have come crashing down to Earth over the last three weeks.

During consecutive losses to Oregon, UCLA and Oregon State, ASU's once stellar defense has looked very average. In their last two games, the Sun Devils have allowed 541 passing yards and seven touchdown passes. Three of those scores have covered 49 yards or more.

So it's not good news that next on ASU's schedule is the 19th-ranked Southern California Trojans, led by the lethal passing combination of quarterback Matt Barkley and receiver Marqise Lee.

"Man, that's what you want to do, you want to play against the best in the country," ASU head coach Todd Graham said Tuesday. "Hands down, this is the best receiving corps in the country and obviously their quarterback will probably be the first guy picked in the draft. They've got some talent."

While USC's record of 6-3 has been a disappointment, the numbers put up by Barkley and Lee have not. Barkley has thrown 30 touchdown passes through nine games, which is tied for second in the nation in that category.

Graham knows that facing Barkley is a huge challenge for the Sun Devil defense.

"Their quarterback is like their offensive coordinator, he calls most of the things at the line, you see him do a lot of checking," he said. "He's very smart, very savvy, and doesn't take a lot of sacks."

Junior cornerback Osahon Irabor also acknowledges that Barkley presents a big threat because of his ability to keep defenses guessing.

"When we're watching film, we noticed that almost every play, he's checking a receiver's route," Irabor said. "As a defense, we've really got to get back to stemming our coverages, which helped us a lot in the beginning of the season to really keep him off-balance and get him playing for us."

Twelve of Barkley's scoring strikes have gone to Lee, who also ranks second nationally with 1,286 receiving yards. In USC's last three games, Lee has obliterated opposing secondaries, catching 34 passes for 605 yards and five touchdowns. Against Arizona, Lee set a Pac-12 record with 345 receiving yards, which is also the fifth-most in a single game in NCAA history.

Last season, the Sun Devils did a decent job of containing Lee, holding him to just 50 yards on four catches -- the fifth-lowest total of his career. That was part of a 41-21 Arizona State win, which gives Irabor and the rest of the defense confidence heading into Saturday's clash at the Los Angeles Memorial Coliseum.

"That was the first time we beat SC in over a decade, so we know we've got the guys to do it -- we know it can be achieved and accomplished," Irabor said. "We're just going to try and work hard this week and get that done."